Image forming device

Abstract

To provide an image forming device that is configured to be able to check orderliness of pages even if a blank page is included therein.SOLUTION: An image forming device 1 is provided with: a page information generating part 13 that applies page information to image data received by a data input part 21; a page information storing part 24 that stores the page information; a preceding page information storing part 25 that stores preceding page information which is page information about a preceding page, on a front surface and a rear surface respectively thereof; a conveyance control part 30 that determines that a blank page is inserted, for the sake of printing; a page information comparing part 27 that checks orderliness of pages, on the basis of a difference between the page information and the preceding page information, on each of the front surface and the rear surface; and a page information adding part 26 that adds an added value to the preceding page information, while referring to an addition table 121 which holds the added value corresponding to the rear surface in both-side printing for the sake of printing, when the blank page for the sake of printing is inserted into the rear surface in both-side printing.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to an image forming apparatus.

Background Art

[0002] Conventionally, in an image forming apparatus, there is a technique for detecting disorder in the page order of a printed page or page omission. For example, a page number is added as header information to a plurality of bitmap data developed by an image developing unit, and a printing apparatus is proposed that collates the page number read from the header information with the page surface of the next page to be printed and stops printing if there is a mismatch (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, an image data generation unit that transmits image data developed in a printable format by a data development unit to a head drive control unit that drives a print head does not generate page information when printing on blank paper (that is, when not printing), or even if page information is generated, it is not transferred to the image data generation unit, so that the sequentiality of the next page cannot be normally determined.

[0005] Here, there are the following two types of printing on blank paper. One is the last page during double-sided printing of an odd-page job or a blank paper inserted on the image forming apparatus side at the time of paper combination insertion (hereinafter referred to as a printing-convenience blank paper). The other is a blank paper actually included in a document to be printed or the like and inserted according to a user's instruction (hereinafter referred to as a user-convenience blank paper).

[0006] Since the print-convenience blank page does not contain data for the job, the image data expansion process is not performed, nor is the page information generated. On the other hand, since the user-convenience blank page contains data for the job, the image data expansion process is performed, and the page information is also generated. However, if the page information thus generated is for a blank page, it is not transferred to the image data generation unit, similar to the image data of the blank page.

[0007] Therefore, for example, when the fourth page is a print-convenience blank page in a print job of double-sided printing of multiple copies of three pages, page information is generated on the back side next to the back side of the first page (the second page), which is the back side of the third page (the fifth page). Thus, the page order cannot be checked.

[0008] Also, in the case of a user-convenience blank page, although page information is generated because it involves the image data expansion process, since this page information is not transferred to the image data generation unit, similarly, the page order cannot be checked.

[0009] An object of the present invention is to provide an image forming apparatus capable of checking the page order even when blank pages are included.

Means for Solving the Problems

[0010] In one aspect, an image forming apparatus includes a data input unit that receives image data, a data expansion unit that expands the image data received by the data input unit into a printable format, a page information generation unit that attaches page information to the image data received by the data input unit, a page information storage unit that stores the page information, a front page information storage unit that stores the front page information, which is the page information of the previous page, on each of the front and back surfaces, a conveyance control unit that determines the insertion of blank pages for printing convenience, a page information comparison unit that checks the page order based on the difference between the page information and the front page information on each of the front and back surfaces, and a page information addition unit that refers to an addition table that holds an addition value corresponding to the back surface of double-sided printing in the printing convenience and adds the addition value to the front page information when the blank page for the printing convenience is inserted on the back surface of the double-sided printing.

Advantages of the Invention

[0011] According to the above aspect, even if blank pages are included, the page order can be checked.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0013] Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings.

[0014] FIG. 1 is a functional block diagram for explaining an image forming apparatus 1 according to an embodiment.

[0015] As shown in FIG. 1, the image forming apparatus 1 includes a controller 10, an image data generation unit 20, a conveyance control unit 30, a head drive control unit 40, and a print head 50.

[0016] The controller 10 includes a data input unit 11, a data expansion unit 12, and a page information generation unit 13.

[0017] The data input unit 11 receives image data (compressed image data) from an external device such as a user terminal, a print control device, or a scanner. For example, the data input unit 11 may acquire the image data from the external device via an interface unit 130 described later.

[0018] The data expansion unit 12 expands the image data received by the data input unit 11 into a printable format (for example, a bitmap format).

[0019] The page information generation unit 13 assigns page information to the image data received by the data input unit 11. This page information is, for example, a value (page number) that increments by one. Hereinafter, the page information will be described as a page number that increments by one. However, if the page information addition unit 26 and the page information comparison unit 27 described later can identify the order of the page information, the page information may be a symbol such as an alphabet, or the increment value may be a number other than 1.

[0020] The image data generation unit 20 includes an image reception unit 21, an image processing unit 22, an image transmission unit 23, a page information storage unit 24, a previous page information storage unit 25, a page information addition unit 26, and a page information comparison unit 27.

[0021] The image receiving unit 21 receives, from the controller 10, data obtained by adding page information by the page information generation unit 13 to the image data developed by the data expansion unit 12. Of the received data, the image receiving unit 21 transfers the developed image data to the image processing unit 22 and causes the page information storage unit 24 to store the page information.

[0022] The image processing unit 22 performs known image processing such as image adjustment on the image data transferred from the image receiving unit 21.

[0023] The image transmission unit 23 transmits the image data on which image processing has been performed by the image processing unit 22 to the head drive control unit 40.

[0024] The page information storage unit 24 stores the page information transferred from the image receiving unit 21.

[0025] The previous page information storage unit 25 stores, on each of the front and back surfaces, the previous page information that is the page information of the previous page. The previous page information storage unit 25 may obtain information as to whether the previous page (target page) is the front surface or the back surface, for example, from the conveyance control unit 30. Note that the page information storage unit 24 and the previous page information storage unit 25 may be a single storage unit. In this case, the storage unit stores the page information and the previous page information in a distinguishable manner.

[0026] The page information addition unit 26 refers to an addition table 121 shown in FIG. 4 that holds addition values for single-sided printing and double-sided printing for each of the printing-convenience blank page and the user-convenience blank page. Then, the page information addition unit 26 reads the previous page information from the previous page information storage unit 25, adds the addition value, and writes it back to the previous page information storage unit 25.

[0027] The page information comparison unit 27 checks the orderliness of the pages based on the differences between the page information and the previous page information for each of the front and back surfaces. If the page information comparison unit 27 determines that the order is in error, it may notify the conveyance control unit 30 or the like and stop the printing. If the page information comparison unit 27 can identify the printing order of the front and back surfaces, the comparison target of the front surface page information may be the back surface page information printed one before, or the comparison target of the back surface page information may be the front surface page information printed one before.

[0028] By the way, when double-sided printing is performed, the number of sheets that can be conveyed simultaneously differs depending on the paper size, so there is a difference in the timing from the start of printing on the front surface to the start of printing on the back surface. For example, as shown in FIG. 5(a), when the paper size is relatively large, the printing is performed in the order of the front surface of the first sheet (page 1), the front surface of the second sheet (page 3), the back surface of the first sheet (page 2), the front surface of the third sheet (page 5), the back surface of the second sheet (page 4), the front surface of the fourth sheet (page 7), the back surface of the third sheet (page 6), the front surface of the fifth sheet (page 9), and the back surface of the fourth sheet (page 8). In this case, the printing of the back surface of the first sheet (page 2) is performed after the printing of the front surface of the first sheet (page 1) and the front surface of the second sheet (page 3).

[0029] On the other hand, as shown in FIG. 5(b), when the paper size is relatively small, the printing is performed in the order of the front surface of the first sheet (page 1), the front surface of the second sheet (page 3), the front surface of the third sheet (page 5), the front surface of the fourth sheet (page 7), the back surface of the first sheet (page 2), the front surface of the fifth sheet (page 9), and the back surface of the second sheet (page 4). In this case, the printing of the back surface of the first sheet (page 2) is performed after the printing of the front surfaces of the first to fourth sheets (pages 1, 3, 5, 7).

[0030] Therefore, the page information comparison unit 27 receives the information of the front and back surfaces from the conveyance control unit 30 on each of the front and back surfaces, compares the page information between the front surfaces and between the back surfaces, and determines the orderliness. As shown in FIGS. 5(a) and 5(b), in the case of double-sided printing, regardless of the printing timing of the back surface, the difference in page information between the front surfaces and between the back surfaces should be 2. Therefore, if the difference is 3 or more, the page information comparison unit 27 may determine it as an error. In the case of single-sided printing, the difference should be 1. Therefore, if the difference is 2 or more, the page information comparison unit 27 may determine it as an error.

[0031] The conveyance control unit 30 acquires, from the controller 10, information such as printing information on whether it is single-sided printing or double-sided printing, paper size, and that the image data developed by the data expansion unit 12 is a blank page (blank page for user convenience). Further, the conveyance control unit 30 determines the insertion of a blank page for printing convenience, for example, at the final page during double-sided printing of an odd-page job or when inserting sheets based on preset settings. Also, the conveyance control unit 30 controls the conveyance unit 70 described later shown in FIG. 2.

[0032] The head drive control unit 40 controls the print head 50 based on the image data received from the image transmission unit 23. The head drive control unit 40 has one or more processors that function as an arithmetic processing device, similar to the control unit 110 described later.

[0033] The print head 50 is, for example, a line-type inkjet head having one or more head modules including a plurality of nozzles that eject ink, and ejects ink onto the paper P shown in FIG. 2. Thereby, the print head 50 performs printing on the paper P. Note that the printing method of the print head 50 is not limited to the inkjet method, and any printing method can be adopted.

[0034] FIG. 2 is a front view showing the internal configuration of the image forming apparatus 1, and FIG. 3 is a block diagram showing the control configuration of the image forming apparatus 1.

[0035] As shown in FIG. 2, the image forming apparatus 1 further includes a paper feeding unit 60, a conveying unit 70, a printing and conveying unit 80, and a paper discharging unit 90.

[0036] Note that the paper P in the present embodiment is an example of a medium, and this medium may be a sheet made of a material other than paper, or a folded object such as an envelope. Therefore, in this specification, paper feeding is an example of supply, and paper discharging is an example of discharge. Thus, paper feeding can be replaced with supply, paper discharging can be replaced with discharge, and paper can be replaced with medium. In FIG. 2, the solid line indicates the conveyance path of the paper P from the external paper feeding unit 61 and the first to third internal paper feeding units 62, 63, 64 to the paper discharging unit 90, and the broken line indicates the switchback path 74 for double-sided printing.

[0037] The paper feeding unit 60 includes an external paper feeding unit 61 and first to third internal paper feeding units 62 to 64. The external paper feeding unit 61 includes a paper feed tray 61a, a paper feed roller 61b, and a separating plate 61c. The external paper feeding unit 61 is disposed, for example, so as to be exposed outside the apparatus housing and feeds the paper P into the apparatus housing.

[0038] The paper feed tray 61a is loaded with the paper P before printing. The paper feed rollers 61b are arranged, for example, in two in the conveyance direction T of the paper P, and feed out and convey the uppermost paper P among the plurality of papers P loaded on the paper feed tray 61a. The separating plate 61c sandwiches the paper P with the paper feed roller 61b and separates the papers one by one.

[0039] The first internal paper feeding unit 62, the second internal paper feeding unit 63, and the third internal paper feeding unit 64 are arranged side by side from top to bottom in this order inside the apparatus housing. Each of the first internal paper feeding unit 62, the second internal paper feeding unit 63, and the third internal paper feeding unit 64 includes a paper feed tray 62a, 63a, 64a on which the paper P before printing is loaded, and paper feed rollers 62b, 63b, 64b that feed out and convey the uppermost paper P among the plurality of papers P loaded on the paper feed trays 62a, 63a, 64a.

[0040] The conveyance unit 70 includes a plurality of conveyance rollers 71, a path switching unit 72, a switchback roller 73, and a switchback path 74. These conveyance rollers 71, path switching unit 72, switchback roller 73, and switchback path 74 circulate the sheet P for double-sided printing and convey it so as to be re-fed to the print head 50.

[0041] The conveyance rollers 71 are arranged in pairs so as to sandwich the sheet P in the conveyance path of the sheet P, for example, and convey the sheet P.

[0042] The path switching unit 72 switches the conveyance path of the sheet P printed by the print head 50 to a path leading to the paper discharge unit 90 and the switchback path 74. The path switching unit 72 is, for example, a flipper. The switchback roller 73 reverses the front and back of the sheet P by switchback-conveying the sheet P in the switchback path 74.

[0043] The print conveyance unit 80 is arranged to face the print head 50 and conveys the sheet P. The print conveyance unit 80 includes a plurality of pulleys 81, a belt 82 wound around these pulleys 81, and a suction fan 83 that sucks air through a plurality of holes provided in the belt 82 to adsorb the sheet P to the belt 82. The print conveyance unit 80 may have a conveyance member other than the belt 82 such as a roller, or may not adsorb the sheet P. Note that the print conveyance unit 80 can be regarded as a part of the conveyance unit 70 that conveys the sheet P together with the conveyance rollers 71 and the like.

[0044] The paper discharge unit 90 includes a paper discharge tray 91 and a paper discharge roller 92. The paper discharge unit 90 is an example of a discharge unit, and is arranged, for example, to be exposed outside the apparatus housing, and discharges the sheet P to the outside of the apparatus housing.

[0045] The printed sheet P is stacked on the paper discharge tray 91. The paper discharge rollers 92 are arranged, for example, in an upper and lower pair, and convey the sheet P toward the paper discharge tray 91.

[0046] The control unit 110 shown in FIG. 3 has one or more processors (e.g., a CPU: Central Processing Unit) that function as an arithmetic processing unit. This processor reads and executes a predetermined program from, for example, the storage unit 120 or from a storage medium (non-transitory computer-readable recording medium) that is detachable from the image forming apparatus 1, thereby functioning as the controller 10, the image data generation unit 20, the conveyance control unit 30, etc. shown in FIG. 1. In this way, the image forming apparatus 1 (the control unit 110 and the storage unit 120) functions as a computer that executes a program. Note that one or more processors may be arranged corresponding to each of the controller 10, the image data generation unit 20, and the conveyance control unit 30, but a processor that also serves as a plurality of the controller 10, the image data generation unit 20, and the conveyance control unit 30 may be arranged.

[0047] The storage unit 120 has one or more memories such as a ROM (Read Only Memory), which is a read-only semiconductor memory in which a predetermined control program is pre-recorded, and a RAM (Random Access Memory), which is a semiconductor memory that can be written to and read from at any time and is used as a working storage area as needed when the processor executes various control programs. The storage unit 120 functions as the page information storage unit 24 and the previous page information storage unit 25 together with the control unit 110.

[0048] The interface unit 130 exchanges various types of information with external devices such as a user terminal, a print control device, and a scanner. For example, the interface unit 130 receives a print job including image data from a user terminal, a print control device, etc.

[0049] Next, an example of adding page numbers will be described with reference to FIG. 6.

[0050] First, in the case of single-sided printing and printing-convenience blank paper shown in Fig. 6(a), the printing-convenience blank paper does not require the expansion process by the data expansion unit 12 and the page number is not assigned by the page information generation unit 13. Therefore, when the third sheet is a blank page (shown by a broken line), the fourth sheet corresponds to the third page. The difference between the page number 3 assigned by the page information generation unit 13 and held by the page information storage unit 24 for the fourth sheet and the page number 2 (second sheet) held by the previous page information storage unit 25 is 1. And since the page information comparison unit 27 determines an error when the difference is 2 or more in the case of single-sided printing, in the case of a difference of 1, it determines that the page order is normal. Therefore, in the case of single-sided printing and printing-convenience blank paper, the page information addition unit 26 does not need to add the addition value.

[0051] Next, in the case of single-sided printing and user-convenience blank paper shown in Fig. 6(b), for the user-convenience blank paper, the expansion process by the data expansion unit 12 and the page number assignment by the page information generation unit 13 are performed. However, since it is a blank page, no data is sent from the controller 10 (data expansion unit 12 and page information generation unit 13) to the image data generation unit 20 (image reception unit 21). Therefore, when the third sheet is a blank page, the difference between the page number 4 assigned by the page information generation unit 13 and held by the page information storage unit 24 for the fourth sheet and the page number 2 (second sheet) held by the previous page information storage unit 25 is 2. And since the page information comparison unit 27 determines an error when the difference is 2 or more in the case of single-sided printing, in the case of a difference of 2, it determines that the page order is in error.

[0052] Therefore, the page information addition unit 26 refers to the addition table 121 shown in FIG. 4 for the third sheet of the user-convenience blank sheet, adds "+1" corresponding to single-sided printing and user-convenience blank sheet to the page number 2 held by the previous page information storage unit 25, and sets it as the page number 3. As a result, the difference between the page number 4 assigned by the page information generation unit 13 for the fourth sheet and held by the page information storage unit 24, and the page number 3 (the third sheet) held by the previous page information storage unit 25 becomes 1. Therefore, the page information comparison unit 27 can determine that the page order is normal.

[0053] Next, the double-sided printing shown in FIGS. 6(c) and (d) will be described. Here, an example where the front and back sides are alternately printed will be described. As shown in FIGS. 5(a) and (b) described above, the printing timing of the back side varies depending on the paper size, but if the page order is checked for each of the front and back sides, the printing timing of the back side will not have an impact.

[0054] Next, in the case of double-sided printing shown in FIG. 6(c) and a printing job with multiple copies of 3 pages where the back sides of the 2nd and 4th sheets are printing-convenience blank sheets, the printing-convenience blank sheets do not require the expansion process by the data expansion unit 12 and the page number is not assigned by the page information generation unit 13. Therefore, after the page number 3 is assigned to the front side of the second sheet by the page information generation unit 13, the page number 4 is assigned to the front side of the third sheet. Similarly, after the page number 6 is assigned to the front side of the fourth sheet by the page information generation unit 13, the page number 7 is assigned to the front side of the fifth sheet. Then, the page numbers 2, 5, and 8 are assigned to the back sides of the 1st, 3rd, and 5th sheets by the page information generation unit 13. Since the page information comparison unit 27 may determine an error if the difference is 3 or more for each of the front and back sides in the case of double-sided printing as described above, in the case of a difference of 3, it will be determined that the page order is in error.

[0055] Therefore, for the back side of the 2nd and 4th sheets of paper that are blank for printing convenience, the page information addition unit 26 refers to the addition table 121 shown in FIG. 4, adds the “+1” corresponding to double-sided printing and blank for printing convenience to the page number 2,5 held by the previous page information storage unit 25, and sets the page number to 3,6. As a result, the difference between the page number 5,8 assigned by the page information generation unit 13 for the back side of the 3rd and 5th sheets of paper and held by the page information storage unit 24, and the page number 3,6 (the back side of the 2nd and 4th sheets of paper) held by the previous page information storage unit 25 is 2. Therefore, the page information comparison unit 27 can determine that the page order is normal.

[0056] Next, when the back side of the 2nd and 4th sheets of paper is blank for user convenience in a double-sided printing job with multiple copies of 4 pages as shown in FIG. 6(d), the blank for user convenience is subjected to the expansion process by the data expansion unit 12 and the page number is assigned by the page information generation unit 13 as described above. However, since it is a blank page, no data is sent from the controller 10 (data expansion unit 12 and page information generation unit 13) to the image data generation unit 20 (image reception unit 21). Therefore, when the back side of the 2nd and 4th sheets of paper is a blank page, the difference between the page number 6,10 assigned by the page information generation unit 13 for the back side of the 3rd and 5th sheets of paper and held by the page information storage unit 24, and the page number 2,6 (the back side of the 1st and 3rd sheets of paper) held by the previous page information storage unit 25 is 4. And since the page information comparison unit 27 should determine an error when the difference is 3 or more in the case of double-sided printing, in the case of a difference of 4, it will be determined that the page order is in error.

[0057] Therefore, the page information addition unit 26 refers to the addition table 121 shown in FIG. 4 with respect to the back side of the third and fourth sheets of the user-convenience blank sheet, adds "+2" corresponding to double-sided printing and user-convenience blank sheet to the page numbers 2 and 6 held by the previous page information storage unit 25, and sets the page numbers to 4 and 8. As a result, the difference between the page numbers 6 and 10 assigned by the page information generation unit 13 with respect to the third and fifth sheets and held by the page information storage unit 24 and the page numbers 4 and 8 (the back side of the third and fourth sheets) held by the previous page information storage unit 25 becomes 2. Therefore, the page information comparison unit 27 can determine that the page order is normal.

[0058] In the above description, an example in which the page information addition unit 26 adds the addition value to the previous page information for each of the printing-convenience blank sheet and the user-convenience blank sheet has been described. However, the page information addition unit 26 may add the addition value to the previous page information for only one of the printing-convenience blank sheet and the user-convenience blank sheet.

[0059] In the embodiment described above, the image forming apparatus 1 includes a data input unit 11 that receives image data, a data expansion unit 12 that expands the image data received by the data input unit 11 into a printable format, a page information generation unit 13 that assigns page information to the image data received by the data input unit 11, a page information storage unit 24 that stores the page information, a previous page information storage unit 25 that stores the previous page information, which is the page information of the previous page, for each of the front and back sides, a conveyance control unit 30 that determines the insertion of a printing-convenience blank page, a page information comparison unit 27 that checks the page order based on the difference between the page information and the previous page information for each of the front and back sides, and a page information addition unit 26 that refers to an addition table 121 that holds an addition value corresponding to the back side of double-sided printing when a printing-convenience blank page is inserted on the back side of double-sided printing as shown in FIG. 6(c) and adds the addition value to the previous page information.

[0060] Also, from the perspective of a page information comparison method for checking the orderliness of pages by a computer, the page information comparison method includes receiving image data, expanding the received image data into a printable format, attaching page information to the received image data, storing the attached page information, storing, for each of the front and back sides, the previous page information which is the page information of the previous page, determining the insertion of blank pages for printing convenience, checking the orderliness of pages based on the difference between the page information and the previous page information for each of the front and back sides, and as shown in FIG. 6(c), when a blank page for printing convenience is inserted on the back side of double-sided printing, referring to an addition table 121 that holds an addition value corresponding to the back side of double-sided printing for printing convenience, and adding the addition value to the previous page information.

[0061] Also, from the perspective of a program, the program causes a computer to realize a function of receiving image data, a function of expanding the received image data into a printable format, a function of attaching page information to the received image data, a function of storing the attached page information, a function of storing, for each of the front and back sides, the previous page information which is the page information of the previous page, a function of determining the insertion of blank pages for printing convenience, a function of checking the orderliness of pages based on the difference between the page information and the previous page information for each of the front and back sides, and as shown in FIG. 6(c), when a blank page for printing convenience is inserted on the back side of double-sided printing, referring to an addition table 121 that holds an addition value corresponding to the back side of double-sided printing for printing convenience, and a function of adding the addition value to the previous page information.

[0062] Incidentally, for the last page during double-sided printing of odd-page jobs or the printing-convenience blank sheets inserted on the image forming apparatus side during sheet insertion, the expansion processing by the data expansion unit 12 is unnecessary and the page number is not assigned by the page information generation unit 13. Therefore, as shown in FIG. 6(c), on the back sides of the 1st, 3rd, and 5th sheets, page numbers 2, 5, and 8 are assigned by the page information generation unit 13, and the difference from the previous page of the page number on the back side becomes 3. Since it exceeds 2 pages, an error determination is made. On the other hand, in the present embodiment, the page information addition unit 26 refers to the addition table 121 shown in FIG. 4 for the back sides of the 2nd and 4th sheets of the printing-convenience blank sheets, and adds the “+1” corresponding to double-sided printing and printing-convenience blank sheets to the page numbers 2 and 5 held by the previous page information storage unit 25 to obtain page numbers 3 and 6. As a result, the difference between the page numbers 5 and 8 assigned by the page information generation unit 13 and held by the page information storage unit 24 for the back sides of the 3rd and 5th sheets and the page numbers 3 and 6 (the back sides of the 2nd and 4th sheets) held by the previous page information storage unit 25 becomes 2. Therefore, the page information comparison unit 27 can determine that the page order is normal. Thus, according to the present embodiment, even if there are printing-convenience blank sheets, the page order can be checked. Therefore, for example, even for printed matter that is difficult to visually check, such as printed matter sealed in a mailing finisher, an abnormality can be detected on the image forming apparatus 1 side, and the occurrence of misenclosure or the like can be prevented.

[0063] Also, in the present embodiment, the addition table 121 holds addition values corresponding to single-sided printing or double-sided printing for user convenience, and when the image data received by the data input unit 11 is a user-convenience blank page, the page information addition unit 26 refers to the addition table 121 and adds the addition value to the previous page information.

[0064] From the perspective of the page information comparison method, the addition table 121 holds addition values corresponding to single-sided printing or double-sided printing according to user convenience. Adding the addition value to the previous page information includes referring to the addition table 121 and adding the addition value to the previous page information when the image data received by the data input unit 11 is a blank page for user convenience.

[0065] From the perspective of the program, the addition table 121 holds addition values corresponding to single-sided printing or double-sided printing according to user convenience. The function of adding the addition value to the previous page information includes referring to the addition table 121 and adding the addition value to the previous page information when the image data received by the data input unit 11 is a blank page for user convenience.

[0066] Incidentally, the user-convenience blank paper that is actually included in a document to be printed and is inserted according to the user's instructions undergoes a development process by the data development unit 12 and is assigned a page number by the page information generation unit 13, but the page number is not transferred to the image data generation unit 20. Therefore, as shown in Fig. 6(b), in single-sided printing, when the third sheet of paper is a blank page, the difference between the page number 4 assigned by the page information generation unit 13 and held by the page information storage unit 24 for the fourth sheet of paper and the page number 2 (the second sheet of paper) held by the previous page information storage unit 25 is 2, resulting in an error determination. Also, as shown in Fig. 6(d), in double-sided printing, when the back sides of the second and fourth sheets of paper are blank pages, the difference between the page numbers 6 and 10 assigned by the page information generation unit 13 and held by the page information storage unit 24 for the back sides of the third and fifth sheets of paper and the page numbers 2 and 6 (the back sides of the first and third sheets of paper) held by the previous page information storage unit 25 is 4, resulting in an error determination. In contrast, in the present embodiment, the page information addition unit 26 refers to the addition table 121 shown in Fig. 4 and adds "+1" corresponding to single-sided printing and user-convenience blank paper or "+2" corresponding to double-sided printing and user-convenience blank paper to the page number held by the previous page information storage unit 25. Thereby, the page information comparison unit 27 can determine that the page order is normal. Therefore, according to the present embodiment, even if there are user-convenience blank pages, the page order can be checked. Thus, for example, even for printed materials such as those sealed in a mailing finisher that are difficult to visually confirm, the image forming apparatus 1 can detect abnormalities and prevent occurrences such as misenclosure.

[0067] Note that the present invention is not limited to the above-described embodiments as they are, and components can be modified and embodied without departing from the gist thereof at the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of components disclosed in the above-described embodiments. For example, all the components shown in the embodiments may be appropriately combined. Needless to say, various modifications and applications are possible within the scope not departing from the gist of the invention. The invention described in the claims of the present application at the time of filing is appended below.

[0068] [Appendix 1] A data input unit that receives image data, A data expansion unit that expands the image data received by the data input unit into a printable format, A page information generation unit that assigns page information to the image data received by the data input unit, A page information storage unit that stores the page information, On each of the front and back surfaces, a front page information storage unit that stores the front page information, which is the page information of the previous page, A conveyance control unit that determines the insertion of blank pages for printing convenience, On each of the front and back surfaces, a page information comparison unit that checks the page order based on the difference between the page information and the front page information, When the blank page for printing convenience is inserted on the back side of double-sided printing, referring to an addition table that holds an addition value corresponding to the back side of double-sided printing in terms of printing convenience, and adding the addition value to the front page information by a page information addition unit An image forming apparatus, characterized by comprising the above.

[0069] [Appendix 2] The addition table further holds addition values corresponding to single-sided printing or double-sided printing for user convenience, When the image data received by the data input unit is a blank page for user convenience, the page information addition unit refers to the addition table and adds the addition value to the front page information The image forming apparatus according to appended note 1, characterized in that...

[0070] [Appended note 3] A data input unit that receives image data, A data expansion unit that expands the image data received by the data input unit into a printable format, A page information generation unit that assigns page information to the image data received by the data input unit, A page information storage unit that stores the page information, On each of the front and back surfaces, a previous page information storage unit that stores the previous page information, which is the page information of the previous page, On each of the front and back surfaces, a page information comparison unit that checks the page order based on the difference between the page information and the previous page information, When the image data received by the data input unit is a blank page for the user's convenience, refer to an addition table that holds an addition value corresponding to single-sided printing or double-sided printing for the user's convenience, and add the addition value to the previous page information. A page information addition unit An image forming apparatus, characterized by comprising...

Explanation of reference numerals

[0071] 1 Image forming apparatus 10 Controller 11 Data input unit 12 Data expansion unit 13 Page information generation unit 20 Image data generation unit 21 Image reception unit 22 Image processing unit 23 Image transmission unit 24 Page information storage unit 25 Previous page information storage unit 26 Page information addition unit 27 Page information comparison unit 30 Conveyance control unit 40 Head drive control unit 50 Print head 60 Paper feeding unit 61 External paper feeding unit 61a Paper feed tray 61b Paper feed roller 61c Deflector 62 First paper feed unit 63 Second paper feed unit 64 Third paper feed unit 62a, 63a, 64a Paper feed trays 62b, 63b, 64b Paper feed rollers 70 Conveyor unit 71 Conveyor roller 72 Path switching unit 73 Switchback roller 74 Switchback path 80 Printing and conveying unit 81 Pulley 82 Belt 83 Suction fan 90 Paper discharge unit 91 Paper discharge tray 92 Paper discharge roller 110 Control unit 120 Memory unit 121 Addition table 130 Interface unit P Paper T Conveying direction

Claims

1. A data input unit that receives image data, A data expansion unit that expands the image data received by the data input unit into a printable format, A page information generation unit that assigns page information to the image data received by the data input unit, A page information storage unit that stores the page information, On each of the front and back surfaces, a previous page information storage unit that stores the previous page information, which is the page information of the previous page, A conveyance control unit that determines the insertion of blank pages for printing convenience, On each of the front and back surfaces, a page information comparison unit that checks the page order based on the difference between the page information and the previous page information, When the blank page for printing convenience is inserted on the back side of double-sided printing, a page information addition unit that refers to an addition table that holds an addition value corresponding to the back side of double-sided printing in terms of printing convenience, and adds the addition value to the previous page information An image forming apparatus, characterized by comprising the above components.

2. The addition table further holds addition values corresponding to single-sided printing or double-sided printing for user convenience, When the image data received by the data input unit is a blank page for user convenience, the page information addition unit refers to the addition table and adds the addition value to the previous page information The image forming apparatus according to claim 1, characterized by the above.

3. A data input unit that receives image data, A data expansion unit that expands the image data received by the data input unit into a printable format, A page information generation unit that assigns page information to the image data received by the data input unit, A page information storage unit that stores the page information, On each of the front and back surfaces, a previous page information storage unit that stores the previous page information, which is the page information of the previous page, On each of the front and back surfaces, a page information comparison unit that checks the page order based on the difference between the page information and the previous page information, When the image data received by the data input unit is a blank page for user convenience, a page information addition unit that refers to an addition table that holds an addition value corresponding to single-sided printing or double-sided printing for user convenience, and adds the addition value to the previous page information An image forming apparatus, characterized by comprising the above components.

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